﻿// Expressions UVA - 10157.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

/*
https://vjudge.net/problem/UVA-10157

Let X be the set of correctly built parenthesis expressions. The elements of X are strings consisting only
of the characters ‘(’ and ‘)’. The set X is defined as follows:
• an empty string belongs to X
• if A belongs to X, then (A) belongs to X
• if both A and B belong to X, then the concatenation AB belongs to X.
For example, the following strings are correctly built parenthesis expressions (and therefore belong
to the set X):
()(())()
(()(()))
The expressions below are not correctly built parenthesis expressions (and are thus not in X):
(()))(()
())(()
Let E be a correctly built parenthesis expression (therefore E is a string belonging to X).
The length of E is the number of single parenthesis (characters) in E.
The depth D(E) of E is defined as follows:
D(E) =



0 if E is empty
D(A) + 1 if E = (A), and A is in X
max(D(A), D(B)) if E = AB, and A, B are in X
For example, the length of “()(())()” is 8, and its depth is 2. What is the number of correctly
built parenthesis expressions of length n and depth d, for given positive integers n and d?
Write a program which
• reads two integers n and d
• computes the number of correctly built parenthesis expressions of length n and depth d;
Input
Input consists of lines of pairs of two integers - n and d, at most one pair on line, 2 ≤ n ≤ 300,
1 ≤ d ≤ 150.
The number of lines in the input file is at most 20, the input may contain empty lines, which you
don’t need to consider.
Output
For every pair of integers in the input write single integer on one line - the number of correctly built
parenthesis expressions of length n and depth d.
Note: There are exactly three correctly built parenthesis expressions of length 6 and depth 2:
(())()
()(())
(()())
Sample Input
6 2
300 150
Sample Output
3
1
*/
#include <iostream>

int main()
{
    std::cout << "Hello World!\n";
}
 